


Two for the Price of One

by RatFlavored



Category: Supernatural
Genre: Crack Treated Seriously, Established Dean Winchester/Sam Winchester, M/M, Polyamory, Porn with Feelings, Tandem bicycle for one, adding a third, diphallia, the duality of man
Language: English
Status: Completed
Published: 2019-07-31
Updated: 2019-07-31
Packaged: 2020-07-28 05:07:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,157
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20058496
Author URL: https://archiveofourown.org/users/RatFlavored/pseuds/RatFlavored
Summary: It’s so clear that they’re made for each other.  Cas realizes he’s made for them.





	Two for the Price of One

**Author's Note:**

> Thank you so much to [Sintari](https://archiveofourown.org/users/OriginalSintari/profile) for beta reading my bs. And thanks to [Satine](https://archiveofourown.org/users/SatinesHell/profile) for encouraging my bullshit.

Although Cas had been interacting with humans for a while now, there were still a vast amount of details to the human experience that he couldn’t grasp.

Clothing was one of them. It served a purpose, to keep warm was the first obvious one. The second was to keep delicate skin from getting in harm's way. Some clothing had a function, such as pockets. But the one time Cas tried to buy clothing based on that particular feature, Dean pulled the cargo shorts from his hands muttering “No fucking way”. But there were so many customs that made little sense. 

Everything had to be tidy, presentable. Sometimes, Dean would mutter that he looked like he rolled out of bed (“I don’t sleep,” he would remind Dean) and he would lean in to straighten out the lapels of his coat, then his tie, wrists close enough that Cas could detect the clove undertones of his cologne. Dean would flip his collar down if it was upturned, or smooth his palms down his shoulders if the cloth was wrinkled. 

Clothing also had to match, coordinate. Sam had once remarked about the off-putting color of one of his ties. It was a “loud” red and green that Sam claimed hurt his eyes. He’d misplaced the blue one and picked up the current offending piece at a thrift store. Ties had no point to them, just a scrap of fabric. But the cobalt blue one that Sam pulled out his closet and handed to him (“Matches your eyes”, Sam said) instilled a purpose into the article. Cas rubbed the pointed tip between his fingers when absorbed in thought. 

The strangest fact about clothing was that people didn’t like when it was off. It was forbidden to go around in the body they’d been born in like every other animal on Earth. Humans were only naked around those they considered close, whether they be an intimate friendship, family, or lovers. Cas had been aware of this for a long time and kept to this simple rule.

Cas’s relationships with humans were limited before the Winchesters. Nothing he’d experienced was anything like the bonds he forged with them. It had transcended beyond friendship to family long ago, but now there was to be a third development. 

It was something that Cas had yearned for from afar, but he assumed there would be no prospect. The two brothers were so in tune with each other, even when they felt they weren’t. Nothing could separate them, even when they tried. Matter and antimatter. It was such a fundamental law that the universe bent to accommodate. They shared a heaven. _Soulmates_. 

So when they offered to let him in, Cas found himself hesitant. Their resonance was built for two. A crest and trough. An atom had protons and electrons; where would he fit in the already balanced equation? Sam and Dean were interdependent. A call and an answer. He’d be unfit to join them.

But they insisted, and like with all of their other requests, Castiel relented. If they wanted him, they could have him. 

If they were to be familiar as lovers, nudity should be fine. 

So when Cas heard the door to the shower room open, he didn’t say a word. Either of them would be more than welcome. 

“Hey,” Dean announced himself and Cas gave him a cursory wave in acknowledgment, back turned as the spray of hot water hit his face. He could hear Dean’s clothes sliding away and wondered if he would allow him to look now. If he understood their recent rearrangement of their relationships and the rules it entailed, it should allow him to see Dean (and Sam) nude. 

Curiosity took hold and Cas stole a peek over his shoulder, eyes traveling up and down. 

Again, Castiel had to speculate why humans had a mandatory rule for clothing at all times. Perhaps it was to cover the mark on his collar. It was one that Sam made. Cas wanted to leave a mark there, too.

His eyes strayed downward again, lingered. 

Just one? Hm. 

Dean looked aroused. Was it sex Dean wanted? Cas licked his lips. 

“Hey, it’s all right,” Dean’s voice was reassuring, and he reached a hand out to rest on Cas’s shoulder, “I’m not here to pressure you into anything. Just here to help wash you up.” 

Did he look nervous? Perhaps he was a little nervous, but Dean’s thumb rubbed a soothing circle into his deltoid that Cas found relaxing. It was a disappointment that Dean had no plans other than hygiene, but that was fine. Dean’s touch sounded nice. 

“Turn around,” Dean coaxed, and Cas did as requested. 

Dean kept determined eye contact as Cas faced him. Dean offered a little smile, eyes crinkling gently that made Cas want to press his lips there. 

When Dean’s spell of politeness had run its course, there was a sweeping of his eyes up and down Cas’s body- then skidded to a halt. 

Dean’s eyes grew big, nearly bulging out of his skull. Cas cocked his head, looking down between them, and back up. Dean’s stare was fastened to his crotch. He blinked a few times. 

“Dean-”

“Sam!” Dean barked, twisting his head to project his voice, but his eyes remained rooted to Castiel’s groin. “Sammy, get in here!” 

Within a couple seconds, Cas heard the shower room door slam open, “Dean?” Sam’s tone was deep and bordering on worried. His eyes widened when he saw the two of them naked and there it was again, the discomfort that came when clothing was not present. Sam averted his eyes, and Cas noticed his cheeks turning red.

“Oh, uh-”

“If Sam wanted to join-” 

“Sam _look_. Theres two. Fucking _two_ of them.”

Sam’s eyes were reluctant, but when they wandered over to him, his eyebrows lifted higher than Cas had ever seen them. His mouth parted, jaw hanging slack in awe. For the first time while naked, Cas felt exposed. 

“Holy fucking shit.”

“Two,” Dean gestured to Cas’s crotch. “Two dicks.”

“Yeah. I see that, Dean.” 

“Two-”

“Is that normal?” Cas looked down at himself and for the first time considered the existence of his genitals. 

Sam looked back up to Cas, “No. Not really.” 

“Hm. I did notice Dean has only one.”

“_Only one-_”

Sam’s lips thinned and a noise escaped his nose. 

“Why is it not normal?” Cas continued, “People have two of everything else. Two ears, two hands, two eyes, two nipples-”

“I don’t have an answer,” Sam explained, “We usually just have one.”

“Looks like God loves you a little extra,” Dean gave a slanted smile with his comment and received an elbow jab from Sam. 

There was a pause in conversation, and Cas felt the awkwardness set in. “So, judging by the reactions from the both of you, is this a negative...situation?”

“No,” Sam’s gaze wandered down again. His eyes glinted and Castiel wished he could know what he was thinking, “No, not at all.”

Dean licked his lips and gave a chin up toward Sam, catching his attention. The two of them shared a series of expressions that Cas tried to parse. A half smile, a nod. It passed through them like light through a sheet of ice. It’s clear that they’re made for each other. 

“Sam, this is completely uncharted territory here.” 

“Good.” 

Dean’s eyes softened on Sam. Warmth. 

That same gaze shifted to him and Cas felt his soul shine alight. Dean placed a hand on the side of Cas’s neck and before he could react, Dean’s lips were on his own. Soft. Then more pressure as Dean’s tongue snuck out to have a taste. When Cas pressed back, Dean pulled away, teasing. 

As soon as Cas could feel the cold void, it was filled with Sam. Both palms on his cheeks, as he leaned down for a kiss. A warm coat in winter. Sam’s fingers cradled his jaw as if he were something precious as he kissed, a slow suck to his lower lip and he was gone. 

Speechless. Cas swallowed. He rolled his lips inward to run his tongue over them. He needed more of them already. 

“Finish up in here, and then you can join us in Dean’s room?” 

“Yes.” Cas breathed out. 

“Don't be too long,” with a wink from Dean the brothers left. 

As the door clicked closed behind them, Cas let out a slow exhale, a proven way to lower his heart rate. He needed to rinse off as quickly as he could. 

\---

As soon as he was acceptable, Cas went straight to Dean’s room. From the context, he knew that clothing would probably soon become optional, so he kept a white towel wrapped around his waist. 

Cas raised a hand to knock, but paused. He heard voices through the door. 

“-called diphallia.” Sam’s voice was punctuated with the sound of key clacks, “Extremely rare.”

“Very neat Sam. Where did you put the lube? We’re gonna need it.”

“Should be in one of the bedside-”

Cas rapped his knuckles on the door and didn't have to wait two seconds until the door opened for him. 

“Hey,” Sam offered a smile. Cas could see behind him that Dean was opening and shutting the bedside table drawers, the Men of Letters robe loosely wrapped around him.. 

Cas glanced downard. The threshold of the room. This space was specifically Sam and Dean’s. 

A hand at the middle of his back. Right between his shoulder blades. Gentle sweep down his spine as Sam guided him in. 

The door shut behind him. Cas glanced down at Sam’s mouth.

“If this is too much, too far too soon-” 

Cas pulled him in by the collar, making their mouths meet. 

There was so much he wanted, and none of it would ever be too much. 

\---

“Remember when we used to split popsicles Sam?” 

“Shut the fuck up.” 

When the two weren’t bantering and their mouths were occupied, they worked wonderfully in tandem. Perfect, blissful synchrony. 

\---

Although the Winchesters had high expectations, Cas wasn’t sure if this would work. One of his cocks inside was already tight. His second rubbed up against the crease of Sam’s ass, smearing an obscene amount of precome all over. 

Dean helped stretch, slick fingers nudging in one by one. 

As Dean carefully pulled Sam apart, they kissed. Deep and slow. Wet and tugging. There was a language between the two that Cas found easy to read. Comforting. 

“All right, Cas,” Dean’s nose brushed against Sam’s, his eyes dark as he kept them locked onto his brother, “Fill him up.”

There was a moment of trepidation (could he handle it?), but Sam nodded and Cas trusted him. He bit his lower lip as he drew back to realign. A groan spilled from his throat as he pushed in with his second cock. So, _so_ good. 

“Oh my god.” Sam sounded hoarse. His hand squeezed Dean’s shoulder, knuckles white, holding onto salvation. Cas bottomed out. He peered down to look at Sam taut and stretched around all of him. Filled to the very edge, right to that limit. 

“You okay?” Dean whispered low, calm. He was staring down over Sam’s shoulder. His eyes were dark and burning. “Holy shit.”

“It’s almost too much,” Cas kept statue still as Sam croaked out the admission, “But it’s amazing. Intense.” 

“Yeah?” Dean reached down, and from the way Sam writhed, Cas assumed he was stroking Sam’s cock. “You love it, don’t you?” 

“Yeah,” Sam glanced back over his shoulder. Those hazel eyes were desperate and pleading as Sam looked up at him. He shifted his hips back. He wanted more. He needed him. As if Cas were the universe itself, he bent. With a hand on Sam’s hip, he started moving. Slow at first. 

“That's it Sammy. You’re doing so good.” Dean’s voice was molten honey. “Think you can suck me? Yeah?” 

Dean led Sam’s mouth downward on his chest to his cock. A groan tore from Dean’s chest as Sam sucked him down. “Oh yeah… take all the cock we give you.”

With one hand in Sam’s hair, Dean gestured at Cas to get him to lean over. “C’mere.”

Whatever they asked of him, Cas would give. 

He leaned in and Dean caught his lips in a kiss. Cas could feel it. The warmth of Dean’s breath in his lungs. He could feel Sam around him, tightening.

“That’s it Cas. Fuck him.” Dean murmured against his lips. 

Cas’s head fell to Dean’s shoulder, mouth at his neck. Sucked and bit. Growled. 

Dean moaned, “Come in him.” 

Sam moaned in echo. 

Cas gave him everything. His body moved on autopilot as he reached climax, his hips mindlessly driving both his cocks deep inside. 

Both Sam and Dean followed seconds behind him, exhausted kisses followed. 

It’s so clear that they’re made for each other. 

And maybe, he was made for them.


End file.
